The invention is based on a shock absorber as defined hereinafter. A shock absorber is already the subject of an earlier patent application Ser. No. 07/390,042 filed Aug. 7, 1989 in which the damping action is variable by means of an electro-magnetic valve assembly. The valve assembly includes the valve body, which depending on the triggering of a magnet coil included in the valve assembly is adjusted variably far toward the valve seat.
In the shock absorber of the earlier application, if the valve body is adjusted forcefully toward the valve seat by a magnetic force of the magnet coil, then pronounced damping of the shock absorber is obtained. If the magnet coil adjusts the valve body toward the valve seat only with a slight magnetic force, then a slight damping of the shock absorber is obtained. Via the triggering of the magnet coil, the damping of the shock absorber can be set arbitrarily between a minimum and a maximum damping.
In the event of a defect, the magnet coil may lose all its current. In that case, with the shock absorber of the earlier application, minimum damping of the shock absorber is necessarily obtained. Although minimum damping by the shock absorber is surely necessary in some extreme situations, still in the case of a defect it is not an optimal compromise.